High performance multi-layer MWIR HgCdTe detector design requires detailed analysis considering the interaction between layers and the nonlinear effects. For this purpose, an in-house numerical model is utilized so that electrical and optical parameters are manipulated to eliminate the undesired performance limits. An ideal detector with perfect crystal quality is expected to have diffusion limited dark current. However, for low operating temperatures (<120K), which is usually the case for the high performance applications, SRH mechanism may dominate dark current especially for alternative substrate detectors and low crystal quality resulting in a short SRH lifetime (similar to 200ns). Here, physical sizes, composition and doping profiles are optimized to suppress generation-recombination (GR) dark current so that cooling burden can be minimized. We numerically achieve similar to 30K (from similar to 85K to similar to 115K) increase on the operating temperature without degrading the system performance parameters for the detection of near room temperature object (300K) by placing a wide bandgap layer inside the bandgap.